Process for molding tooth-crowns and the like.



S. SHIMURA & Y. MINAGAWA.

PROCESS FOR MOLDING TOOTH OROWNS AND THE LIKE.

APPLICATION FILED DEC. 16, 1907.

909,696, Patented Ja11.12,l909.

2'SHEET8SHEET l.

WITNESSES INVENTORY S. SHIMURA & Y. MINAGAWA.

PROCESS FOR MOLDING TOOTH CBOWNS AND THE LIKE.

- APPLICATION FILED DEO.16, 1907.

909,696. I Patented Jan. 12, 1909.

2 snna'rewsnzzi' 2.

QA f w/ 6.

A TTORNE YS rm: NORRIS PETERS 0a.. WASHINGTON. u. c.

SEIMARO SHIMURA AND YOSHIZO MINAGAWA, OF TOKYO, JAPAN.

PROCESS FOR MOLDING TOOTH-GROWNS AND THE LIKE.

Specification of Letters Patent.

Patented Jan. 12, 1909.

Application filed December 16, 1907. Serial No. 406,820.

T 0 all whom it may concern:

Be it known that we, SEIMARO SHIMURA and Yosnizo MINAGAWA, subjects ofthe Emperor of Japan, residing, respectively, at No. 20 Gofuku-cho, Nihombashi-ku, city of Tokyo, Japan, and at No. 6 Tomizawa-cho,Nihombashi-ku, city of Tokyo, Japan, have invented new and usefulImprovements in Proc esses for Molding Tooth-Crowns and the Like; and wedo hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

The object consists of obtaining a perfect occlusion, securing thereby apermanency of the cusps in crowns and bridges and also obtaining aperfect and easy fit of the gold inlays.

Figure 1 shows a perspective of one of the half boxes used as a part ofa mold for carrying out our invention; Fig. 2 is a perspec tive of theother half mold; Fig. 3 is a perspective of the mold complete; Fig. 4 isa section showing the channels for facilitating the pouring of themolten metal.

In order to make gold tooth crowns provided with cusps and bridges, weproceed as follows: l/Ve first fit in the ordinary way, a gold band inthe patients mouth, and place opposite this band, that is, upon theopposing jaw, a piece of softened modeling composition, and then squeezethe latter between the jaw carrying the band, and a tooth in the otherjaw and opposite the band. An impression is made conveniently by closingthe teeth together so as to secure an impression from the tooth oppositethe band. The composition is now allowed to stand and is removedtogether with the band. The composition member is now trimmed andsmoothed down with cuttle fish disks or other mechanical appliances, andis next separated from the band. We will designate the member thuscompleted, as the pattern. We next take the two-part mold (see A, B,Figs. 1 and 2) and fill the half A with a thick creamy paste consistingof one part plaster of paris and two parts oxid of lead.

The face of the paste being smooth and fiush with the upper surface ofthe part A, the pattern is forced partially into the paste, as shown inFig. 4, a portion of the surface being left exposed and protrudingslightly from the paste. The paste is now allowed to dry, whereupon itbecomes hard. The entire surface is now given a thin coating of oil orvarnish. The part B of the mold is now filled with the same kind ofpaste and the two members A and B of the mold are placed face to faceand secured together as indicated in Fig. 3. The entire mold and itscontents are now warmed and the member B carefully removed. The patternis next taken out and the paste is out slightly so as to form channels5, the latter registering with the semi-circular openings 0, c, in thetwo parts of the mold. The two parts of the mold are next placedtogether and are sealed all around with the mixture, the channels I)being left face to face so that there is a clear opening through thepaste, this opening being substantially funnel shaped in order tofacilitate pouring the molten metal into the mold. The entire mold andits contents are now dried by the aid of a gas blower, and whencompletely dry, molten gold is poured into the mold through the funnelshaped opening. The gold is melted in a crucible made for the purpose.

lVhat we claim is as follows:

The process herein described, of molding artificial teeth and the like,which consists in forming a model of the article to be molded, preparinga plastic mixture, filling said plastic mixture into a half box,insert-' ing said model partially into said plastic mixture, allowingsaid plastic mixture to harden, oiling the surface of the hardenedmixture, then filling another half box with plastic composition, nextplacing the two half boxes together so that said model buries itselfpartially in the mixture held by the half box last prepared, nextwarming the two half boxes and their contents, next separating the twohalf boxes, removing the model, cutting channels from the exterior ofthe half boxes to the cavity formerly occupied by the model, and pouringthrough said channels into said cavity the materials to form theartificial teeth.

In testimony whereof we have signed our names to this specification inthe presence of two subscribing witnesses.

SEIMARO SHIMURA. YOSHIZO MINAGAWA. l/Vitnesses:

J AMES B. DAVIES, LELAND HARRISON.

